1. Field of the Invention
The invention concerns a lubricating and cooling device for intershaft bearings in turbomachines. It includes means for supplying consumable lubricating fluid and pressurized air, as well as means for distributing the atomized lubricating fluid.
2. Description of the Prior Art
There exist known systems for lubricating and cooling bearing blocks in the form of roller bearings turning at high speeds. More particularly, there exist devices that fulfill the lubricating function using either a mist of oil and pressurized air or a stream of oil that is then removed by the cooling air. Such known systems are described in French Pat. No. 1,235,469, where they perform lubrication of a roller bearing seated in a fixed housing. The housing contains two chambers: a peripheral chamber outside the bearing, and an axial chamber extending said bearing. The outer chamber receives compressed air through a channel connecting the axial chamber through openings into which the pressurized oil supply nozzels also run. Compressed air surrounds the stream of oil and prevents it from being atomized before it makes contact with the roller bearing. The oil-air mixture is evacuated after having crossed over the roller bearing. Such a system is adapted to a bearing placed between a fixed piece and a shaft, and cannot be used for a bearing lying between two shafts.
French Pat. No. 2,359,975 also deals with the lubrication of a bearing that supports the end of a turbine shaft. The outer ring of the bearing is seated in a fixed housing. The chamber defined between the end of the shaft and the seat is provided with an annular distributor that receives lubricating and cooling fluid and compressed air. The fluid used is fuel injected under pressure by the main pump. The air-fuel mixture is projected into the journal cavity of the bearing through the axial passages of the annular distributor. After cooling and lubricating the bearing, the mixture joins the engine exhaust gases through passages provided for this purpose. As in the first patent, the lubricating device described is applicable only to a bearing held within a fixed housing inside which or upon which the distributor of the lubricating fluid can be fastened.